COASTLOOC data paper

Figures for the paper

This section shows the figures that I think should be included in the data paper.

Figure 1

Figure 1: Map of the sampling stations. The three black outlines in the bottom panels (Mediterranean Sea and North Sea) identify the stations and the transects used in Fig. 5E (C100) as well as for the examples of vertical profiles of \(K_{\text{Ed}}(490)\) in Fig. 8 (C401 and C606).

Figure 2

Figure 2: (A) Overview of the temporal sampling for the six areas. The numbers in the circles indicate the number of visited stations each month. (B) Boxplot showing the bathymetry at the sampling locations by area. The labels on top of each circle identify the COASTLOOC campaigns (C1 to C6).

Figure 3

(A) Vertical profile of the upwelling irradiance taken on 11 April 1997 at station C1021 located in the North-East Atlantic offshore Northern Portugal. A double deep chlorophyll maximum with the corresponding irradiance increase due to chlorophyll fluorescence is observed at water depths of ca. 35 m and 45 m, most prominently at 683 nm, but also at 664 nm and even at 706 nm. Attenuation in the blue to green wavelengths is correspondingly enhanced as reflected by the change in slope at a depth of ca. 34 m. (B) Vertical profiles of the upwelling and downwelling irradiance taken on 25 September 1998 at station C6176 located in the Baltic Sea offshore Usedom Island in North-East Germany. Baltic Sea waters are rich in CDOM, resulting in strong absorption in the UV and blue. The reduced decrease of the upwelling irradiance at 559 nm towards larger depths is likely caused by reflection of downwelling irradiance from the ocean bottom. Chlorophyll fluorescence is likely the reason for the relatively enhanced upwelling irradiance at 683 nm for depths below ca. 7 m.

Figure 4

Figure 4: (A) Total chlorophyll a and (B) particulate organic carbon across the sampled areas.

Figure 5

Figure 5: (A) Average total particulate (\(a_\text{p}\)), (B) non-algal (\(a_\text{NAP}\)), (C) phytoplankton (\(a_{\phi}\)) and (D) chromophoric dissolved organic matter (\(a_\text{CDOM}\)) absorption spectra in each area. (E) \(a_\text{CDOM}(350)\) along the westernmost transect in the North Sea (see Fig. 1B).

Figure 6

Figure 6: (A) Particulate scattering coefficient at 440 nm (\(b_{b}(440)\)) and (B) attenuation coefficient for downward irradiance at 443 nm (\(K_{\text{Ed}}(443)\)) across the sampled areas.

Figure 7

Figure 7: Subsurface reflectance \(R~(0^{-})\) across the sampled areas. The thick lines represent the regional averages. Note that \(R~(0^{-})\) at wavelengths above 705 nm could only be derived from helicopter-based measurements.

Figure 8

(A) \(K_{\text{Ed}}(490)\) profiles taken in the Lion’s Gulf on 30. Sept. 1997 along a transect extending from site C4014 located ca. 5 km to the west of the mouth of the main Rhône branch (Grand Rhône) to site C4019 located some 20 km further south in clear Mediterranean waters. (B) \(K_{\text{Ed}}(490)\) profiles taken in the North Sea on 12. Sept 1998 along a transect extending from site C6063 close to the western shore of the island of Texel to site C6069 located ca. 22 km further west in the open North Sea.

Figure 9

Scatterplots showing relationships among different selected variables. (A) Particulate organic carbon (POC) and (B) phytoplankton absorption at 443 nm (\(a_{\phi}(443)\)) against total chlorophyll a. (C) Downward irradiance at 443 nm (\(K_{\text{Ed}}(443)\)) and (D) particulate scattering at 440 nm (\(b_{b}(440)\) against particulate organic carbon. The red lines show the linear relationships between the variables. The shaded gray areas represent the 95% confidence intervals around the fitted models.

Appendix 1

Example of extrapolation of the upward irradiance towards the sea surface. The irradiance values just below the sea surface (red crosses, \(E_u~(0^{-})\)) and the corresponding diffuse attenuation coefficient for the topmost water layer are specified in the figures. The full lines represent the interpolated values whereas the dashed lines show extrapolation values up to the sea surface.

Done

  • Validated that there are no absorption for Med. Sea Case 1 cruise.

  • A few stations were located on the land (bad geographical coordinates). They have been removed.

  • Calculate s_nap and s_cdom. See the method in Babin et al. (2003) where he removes some wavelengths to calculate s_nap.

  • Removed dissolved a and c from the AC9 data because there were problems with the filtering procedure during the sampling. These correspond to the ad and cd variables in SurfaceData5(C4corr).txt.

  • Extract bathymetry at each station.

  • Zoom on geographic areas in Fig. 1 such as figure 13 in the final report.

  • Validated that are only two AC9 measurements in the Adriatic Sea.

  • Removed duplicated radiometric surface spectral profiles (duplicated Ed/Eu/Kd/Ku).

  • Removed Almofront (A2, Med case 1) observations as they were collected from a separate mission with different funding.

TODO

References

Babin, Marcel, André Morel, Vincent Fournier-Sicre, Frank Fell, and Dariusz Stramski. 2003. “Light Scattering Properties of Marine Particles in Coastal and Open Ocean Waters Asrelated to the Particle Mass Concentration.” Limnology and Oceanography 48 (2): 843–59. https://doi.org/10.4319/lo.2003.48.2.0843.